1. 16 Jan, 2017 3 commits
  2. 14 Jan, 2017 1 commit
    • Masami Hiramatsu's avatar
      kprobes, extable: Identify kprobes trampolines as kernel text area · 5b485629
      Masami Hiramatsu authored
      Improve __kernel_text_address()/kernel_text_address() to return
      true if the given address is on a kprobe's instruction slot
      trampoline.
      
      This can help stacktraces to determine the address is on a
      text area or not.
      
      To implement this atomically in is_kprobe_*_slot(), also change
      the insn_cache page list to an RCU list.
      
      This changes timings a bit (it delays page freeing to the RCU garbage
      collection phase), but none of that is in the hot path.
      
      Note: this change can add small overhead to stack unwinders because
      it adds 2 additional checks to __kernel_text_address(). However, the
      impact should be very small, because kprobe_insn_pages list has 1 entry
      per 256 probes(on x86, on arm/arm64 it will be 1024 probes),
      and kprobe_optinsn_pages has 1 entry per 32 probes(on x86).
      In most use cases, the number of kprobe events may be less
      than 20, which means that is_kprobe_*_slot() will check just one entry.
      Tested-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
      Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
      Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
      Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Andrey Konovalov <andreyknvl@google.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Jiri Olsa <jolsa@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Link: http://lkml.kernel.org/r/148388747896.6869.6354262871751682264.stgit@devbox
      [ Improved the changelog and coding style. ]
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      5b485629
  3. 12 Jan, 2017 1 commit
    • Ingo Molnar's avatar
      Merge tag 'perf-core-for-mingo-4.11-20170111' of... · f913f3a6
      Ingo Molnar authored
      Merge tag 'perf-core-for-mingo-4.11-20170111' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core
      
      Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:
      
      New features:
      
      - Add more triggers to switch the output file (perf.data.TIMESTAMP).
      
        Now, in addition to switching to a different output file when
        receiving a SIGUSR2, one can also specify file size and time based
        triggers:
      
             perf record -a --switch-output=signal
      
        is equivalent to what we had before:
      
             perf record -a --switch-output
      
        While we can also ask for the file to be "sliced" by size, taking
        into account that that will happen only when we get woken up by
        the kernel, i.e. one has to take into account the --mmap-pages (the
        size of the perf mmap ring buffer):
      
             perf record -a --switch-output=2G
      
        will break the perf.data output into multiple files limited to 2GB
        of samples, right when generating the output.
      
        For time based samples, alert() will be used, so to have 1 minute
        limited perf.data output files:
      
            perf record -a --switch-output=1m
      
        (Jiri Olsa)
      
      - Remove the need to use -e only for syscalls and --event only for
        tracepoints/HW/SW/etc events, i.e. now one can use:
      
            perf trace -e nanosleep,futex,sched:sched_switch ./workload
      
        or:
      
            perf trace --event nanosleep,futex,sched:sched_switch ./workload
      
        And have it tracing raw_syscalls:sys_{enter,exit} for the nanosleep
        and futex syscalls, formatting those as strace does while also
        tracing sched:sched_switch, ordering it all into one strace like
        output.
      
        Using '!' as the first character in the -e/--event argument remains
        a way to negate the list of syscalls, i.e. all syscalls except for
        the ones specified, doesn't affect the other kinds of events.
      
        E.g:
      
        [root@jouet ~] # perf trace -e sched:sched_switch,nanosleep usleep 1
           0.000 ( 0.028 ms): usleep/28150 nanosleep(rqtp: 0x7ffe4201b9f0) ...
           0.028 (         ): sched:sched_switch:usleep:28150 [120] S ==> swapper/0:0 [120])
           0.000 ( 0.065 ms): usleep/28150  ... [continued]: nanosleep()) = 0
        [root@jouet ~]#
      
        (Arnaldo Carvalho de Melo)
      
      - 'perf kallsyms' toy tool to look for extended symbol information on
        the running kernel and demonstrate the machine/thread/symbol APIs for
        use in other tools, such as 'perf probe' (Arnaldo Carvalho de Melo)
      
      Infrastructure improvements:
      
      - Add missing linux/kernel.h include to subcmd.h (Arnaldo Carvalho de Melo)
        tools: Sync x86's vmx.h with the kernel
      
      - Create libdir directory before installing libperf-jvmti.so (Laura Abbott)
      
      - Fix typo in perf_evlist__start_workload() (Soramichi Akiyama)
      Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      f913f3a6
  4. 11 Jan, 2017 15 commits
  5. 05 Jan, 2017 2 commits
    • David Carrillo-Cisneros's avatar
      perf/x86: Set pmu->module in Intel PMU modules · 74545f63
      David Carrillo-Cisneros authored
      The conversion of Intel PMU drivers into modules did not include reference
      counting. The machine will crash when attempting to  access deleted code
      if an event from a module PMU is started and the module removed before the
      event is destroyed.
      
      i.e. this crashes the machine:
      
      	$ insmod intel-rapl-perf.ko
      	$ perf stat -e power/energy-cores/ -C 0 &
      	$ rmmod intel-rapl-perf.ko
      
      Set THIS_MODULE to pmu->module in Intel module PMUs so that generic code
      can handle reference counting and deny rmmod while an event still exists.
      Signed-off-by: default avatarDavid Carrillo-Cisneros <davidcc@google.com>
      Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Dave Hansen <dave.hansen@linux.intel.com>
      Cc: Jiri Olsa <jolsa@redhat.com>
      Cc: Kan Liang <kan.liang@intel.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Paul Turner <pjt@google.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
      Cc: Stephane Eranian <eranian@google.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Link: http://lkml.kernel.org/r/1482455860-116269-1-git-send-email-davidcc@google.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      74545f63
    • Ingo Molnar's avatar
      Merge tag 'perf-urgent-for-mingo-4.10-20170104' of... · 4e06d4f0
      Ingo Molnar authored
      Merge tag 'perf-urgent-for-mingo-4.10-20170104' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent
      
      Pull perf/urgent fixes and one improvement from Arnaldo Carvalho de Melo:
      
      Fixes:
      
        - Fix prev/next_prio formatting for deadline tasks in libtraceevent (Daniel Bristot de Oliveira)
      
        - Robustify reading of build-ids from /sys/kernel/note (Arnaldo Carvalho de Melo)
      
        - Fix building some sample/bpf in Alpine Linux 3.4 (Arnaldo Carvalho de Melo)
      
        - Fix 'make install-bin' to install libtraceevent plugins (Arnaldo Carvalho de Melo)
      
        - Fix 'perf record --switch-output' documentation and comment (Jiri Olsa)
      
        - Fix 'perf probe' for cross arch probing (Masami Hiramatsu)
      
      Improvement:
      
        - Show total scheduling time in 'perf sched timehist' (Namhyumg Kim)
      Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      4e06d4f0
  6. 04 Jan, 2017 2 commits
  7. 03 Jan, 2017 6 commits
  8. 02 Jan, 2017 1 commit
    • Masami Hiramatsu's avatar
      perf probe: Fix to get correct modname from elf header · 1f2ed153
      Masami Hiramatsu authored
      Since 'perf probe' supports cross-arch probes, it is possible to analyze
      different arch kernel image which has different bits-per-long.
      
      In that case, it fails to get the module name because it uses the
      MOD_NAME_OFFSET macro based on the host machine bits-per-long, instead
      of the target arch bits-per-long.
      
      This fixes above issue by changing modname-offset based on the target
      archs bit width. This is ok because linux kernel uses LP64 model on
      64bit arch.
      
      E.g. without this (on x86_64, and target module is arm32):
      
        $ perf probe -m build-arm/fs/configfs/configfs.ko -D configfs_lookup
        p:probe/configfs_lookup :configfs_lookup+0
                                ^-Here is an empty module name.
      
      With this fix, you can see correct module name:
      
        $ perf probe -m build-arm/fs/configfs/configfs.ko -D configfs_lookup
        p:probe/configfs_lookup configfs:configfs_lookup+0
      Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
      Cc: Jiri Olsa <jolsa@redhat.com>
      Cc: Namhyung Kim <namhyung@kernel.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Link: http://lkml.kernel.org/r/148337043836.6752.383495516397005695.stgit@devboxSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      1f2ed153
  9. 01 Jan, 2017 2 commits
    • Linus Torvalds's avatar
      Linux 4.10-rc2 · 0c744ea4
      Linus Torvalds authored
      0c744ea4
    • Linus Torvalds's avatar
      Merge branch 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm · 4759d386
      Linus Torvalds authored
      Pull DAX updates from Dan Williams:
       "The completion of Jan's DAX work for 4.10.
      
        As I mentioned in the libnvdimm-for-4.10 pull request, these are some
        final fixes for the DAX dirty-cacheline-tracking invalidation work
        that was merged through the -mm, ext4, and xfs trees in -rc1. These
        patches were prepared prior to the merge window, but we waited for
        4.10-rc1 to have a stable merge base after all the prerequisites were
        merged.
      
        Quoting Jan on the overall changes in these patches:
      
           "So I'd like all these 6 patches to go for rc2. The first three
            patches fix invalidation of exceptional DAX entries (a bug which
            is there for a long time) - without these patches data loss can
            occur on power failure even though user called fsync(2). The other
            three patches change locking of DAX faults so that ->iomap_begin()
            is called in a more relaxed locking context and we are safe to
            start a transaction there for ext4"
      
        These have received a build success notification from the kbuild
        robot, and pass the latest libnvdimm unit tests. There have not been
        any -next releases since -rc1, so they have not appeared there"
      
      * 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
        ext4: Simplify DAX fault path
        dax: Call ->iomap_begin without entry lock during dax fault
        dax: Finish fault completely when loading holes
        dax: Avoid page invalidation races and unnecessary radix tree traversals
        mm: Invalidate DAX radix tree entries only if appropriate
        ext2: Return BH_New buffers for zeroed blocks
      4759d386
  10. 30 Dec, 2016 2 commits
  11. 29 Dec, 2016 2 commits
    • Olof Johansson's avatar
      mm/filemap: fix parameters to test_bit() · 98473f9f
      Olof Johansson authored
       mm/filemap.c: In function 'clear_bit_unlock_is_negative_byte':
        mm/filemap.c:933:9: error: too few arguments to function 'test_bit'
          return test_bit(PG_waiters);
               ^~~~~~~~
      
      Fixes: b91e1302 ('mm: optimize PageWaiters bit use for unlock_page()')
      Signed-off-by: default avatarOlof Johansson <olof@lixom.net>
      Brown-paper-bag-by: default avatarLinus Torvalds <dummy@duh.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      98473f9f
    • Linus Torvalds's avatar
      mm: optimize PageWaiters bit use for unlock_page() · b91e1302
      Linus Torvalds authored
      In commit 62906027 ("mm: add PageWaiters indicating tasks are
      waiting for a page bit") Nick Piggin made our page locking no longer
      unconditionally touch the hashed page waitqueue, which not only helps
      performance in general, but is particularly helpful on NUMA machines
      where the hashed wait queues can bounce around a lot.
      
      However, the "clear lock bit atomically and then test the waiters bit"
      sequence turns out to be much more expensive than it needs to be,
      because you get a nasty stall when trying to access the same word that
      just got updated atomically.
      
      On architectures where locking is done with LL/SC, this would be trivial
      to fix with a new primitive that clears one bit and tests another
      atomically, but that ends up not working on x86, where the only atomic
      operations that return the result end up being cmpxchg and xadd.  The
      atomic bit operations return the old value of the same bit we changed,
      not the value of an unrelated bit.
      
      On x86, we could put the lock bit in the high bit of the byte, and use
      "xadd" with that bit (where the overflow ends up not touching other
      bits), and look at the other bits of the result.  However, an even
      simpler model is to just use a regular atomic "and" to clear the lock
      bit, and then the sign bit in eflags will indicate the resulting state
      of the unrelated bit #7.
      
      So by moving the PageWaiters bit up to bit #7, we can atomically clear
      the lock bit and test the waiters bit on x86 too.  And architectures
      with LL/SC (which is all the usual RISC suspects), the particular bit
      doesn't matter, so they are fine with this approach too.
      
      This avoids the extra access to the same atomic word, and thus avoids
      the costly stall at page unlock time.
      
      The only downside is that the interface ends up being a bit odd and
      specialized: clear a bit in a byte, and test the sign bit.  Nick doesn't
      love the resulting name of the new primitive, but I'd rather make the
      name be descriptive and very clear about the limitation imposed by
      trying to work across all relevant architectures than make it be some
      generic thing that doesn't make the odd semantics explicit.
      
      So this introduces the new architecture primitive
      
          clear_bit_unlock_is_negative_byte();
      
      and adds the trivial implementation for x86.  We have a generic
      non-optimized fallback (that just does a "clear_bit()"+"test_bit(7)"
      combination) which can be overridden by any architecture that can do
      better.  According to Nick, Power has the same hickup x86 has, for
      example, but some other architectures may not even care.
      
      All these optimizations mean that my page locking stress-test (which is
      just executing a lot of small short-lived shell scripts: "make test" in
      the git source tree) no longer makes our page locking look horribly bad.
      Before all these optimizations, just the unlock_page() costs were just
      over 3% of all CPU overhead on "make test".  After this, it's down to
      0.66%, so just a quarter of the cost it used to be.
      
      (The difference on NUMA is bigger, but there this micro-optimization is
      likely less noticeable, since the big issue on NUMA was not the accesses
      to 'struct page', but the waitqueue accesses that were already removed
      by Nick's earlier commit).
      Acked-by: default avatarNick Piggin <npiggin@gmail.com>
      Cc: Dave Hansen <dave.hansen@linux.intel.com>
      Cc: Bob Peterson <rpeterso@redhat.com>
      Cc: Steven Whitehouse <swhiteho@redhat.com>
      Cc: Andrew Lutomirski <luto@kernel.org>
      Cc: Andreas Gruenbacher <agruenba@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Mel Gorman <mgorman@techsingularity.net>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b91e1302
  12. 28 Dec, 2016 3 commits